((mj:Measles or mj:"Measles virus" or ti:(Measles or Saramp* or "Edmonston virus" or "Virus Edmonston")) (mh:("Disease Outbreaks" or Epidemics or Pandemics) or ti:(surto or surtos or brote or brotes or outbreak$ or epidemia$ or epidemic$ or pandemi$)) and da:20$)